Lock washer and lock washer assembly



y 1957 c. o. OLDENKOTT 3,329,190

LOCK WASHER AND LOCK WASHER ASSEMBLY Original Filed Nov. 26, 1965 24PEG! F'iG. 6

INVENTOR.

CARL O. OLDENKO'TT ATTORNEY United States Patent 3,329,190 LOCK WASHERAND LOCK WASHER ASSEMBLY Carl 0. Oldenkott, 213 N. Evergreen, Anaheim,Calif. 92805 Continuation of application Ser. No. 509,972, Nov. 26,1965. This application Aug. 30, 1966, Ser. No. 576,161 1 Claim. (Cl.151-35) This application is a continuation of my application Ser. No.509,972, filed Nov. 26, 1965, entitled Lock Washer and Lock WasherAssembly, now abandoned.

The present invention relates generally to mechanical fasteners, andmore particularly to a lock washer and lock washer assembly for lockinga nut on a stud bolt or through bolt.

A major object of the present invention is to provide a lock washer ofsimple design, which together with another washer of the same structure,may, when both Washers are disposed in an encircling position on anexternally threaded elongate member, cooperatively hold a nut in afixed, non-rotatable position on the member. Another object of theinvention is to supply a lock washer assembly which includesconventional nuts and studs or through bolts wherein the lockingfunction is attained by means of the particular configuration of thelocking washers.

Yet another object of the present invention is to furnish lock washerswhich are adapted to be assembled in pairs to perform the function oflocking a nut on a stud or through bolt when the nut is merely rotatedinto place in pressure contact with an external surface of one of thelock washers.

Still another object of the present invention is to furnish a pair oflock washers having opposed cooperating cam faces which function whenthe lock Washers are assembled to prevent rotation of a nut in anunlocking direction dur ing the normal intended use of the lock washerassembly.

A further object of the invention is to supply a lock washer, on oneside of which 0am faces are formed that can cooperate with cam facesformed on a duplicate lock washer, with the side of each lock washeropposite that on which cam faces are formed having serrations or othermeans which can operatively engage adjacent metal surfaces, such as thebottom or lower surface of a nut, the top surface of a sequence ofplates, or other members disposed between the nut and the base of a studbolt or the head of a through bolt, as the case may be, to effectlocking engagement between the nut and stud bolt or through bolt onwhich the lock washers are mounted.

A still further object of the present invention is to provide a lockwasher assembly having cooperating cam faces which are sufficientlywithin a range of angularity that a nut may be locked on a stud bolt orthrough bolt when the nut is rotatably brought into its locking orengaging position.

Yet another object of the invention is to provide lock washers havingopposed matching flats on the outer surfaces thereof, which areassembled in pairs, which flats cooperatively receive a wrench wherebythe washers and nut are adapted to be removed from the stud out of afully locked position.

Still a further object of the invention is to provide a lock washerintended for paired assembly and having a plurality of stop shouldersformed on the engaging cam surfaces thereof, which shoulders upon mutualcontact, c0- operatively arrest relative rotation between the two lockwashers during the time the nut is screwed onto a stud bolt or throughbolt, as the case may be.

These and other objects and advantages of the present invention Willbecome apparent from the following description of a first and alternateforms thereof, and from the accompanying drawing illustrating the same,in which:

FIGURE 1 is an exploded perspective view of the first form of theinvention prior to assembly;

FIGURE 2 is a perspective view of the invention after assembly;

FIGURE 3 is a top plan view of one of the lock washers taken on the line3-3 of FIGURE 1;

FIGURE 4 is a top plan View of the lowermost lock washer shown in FIGURE1, taken on the line 4-4 thereof;

FIGURE 5 is a side elevational View of a through bolt with two of thelock washers mounted thereon and resting on the uppermost surface of tworigid members through which the bolt extends, with the nut for the boltbeing in contact with the uppermost washer;

FIGURE 6 is a side elevational view of the alternate form of lockwasher; and

FIGURE 7 is an enlarged side elevational view of the first form ofwasher taken on the line 7-7 of FIGURE 4.

With continuing reference to the drawing for the general arrangement ofthe invention, it will be seen that a stud bolt 12 projects upwardlyfrom a stud base 14 and is rigidly connected thereto. External threads16 are formed on the stud bolt 12,- which bolt extends through a bolthole 10 in a rigid plate A that rests on the upper surface of the base14. The upper surface 18 of plate A is adapted to have a lower lockwasher 20 rest thereon, as may best be seen in FIGURE 2, and an upperlock washer 22 rests on top of washer 20. A nut 24 is in lockedoperative position above washer 22.

A central opening 26 is formed in the lower washer 20, and a centralopening 28 in the upper washer 22 to permit these washers to be slidover the stud bolt 12 from the position shown in FIGURE 1 to occupy theposition shown in FIGURE 2. The openings 26 and 28 are just large enoughto permit the easy mounting of washers 20 and 22 on the stud bolt 12prior to engagement of the stud bolt by the nut 24. Nut 24 may then beplaced in engagement with stud bolt 12, with the interior threads 25 ofthe nut (FIGURE 5) engaging the threads 16 on the outside of stud bolt12. Thereafter, clockwise rotation of nut 24 (FIGURE 2) will lower it onstud bolt 12 due to engagement between threads 25 and 16 until the nutis in a locked position.

Serrations 30 are formed on the lower face of washer 20, and serrations32 are formed on the upper face of washer 22, which consist materiallyin maintaining the nut 24 in a locked, non-rotatable position on studbolt 12. As nut 24 is lowered on stud bolt 12 in the manner described,it forces lock washers 20 and 22, plate A, and the stud base 14 intocompressive engagement, thereby causing serrations 30 to engage and biteinto the upper surface 18 of the plate, and also causing serrations 32to engage and bite into the lower surface 36 of the nut. Also, theengagement of serrations 30 with the top surface 18 of plate A serves tohold lower washer 20 against further rotation, while the engagement ofserrations 32 with the lower surface 36 of nut 24 causes washer 22 torotate in a clockwise direction with nut 24 until stopped by coming intocontact with stop shoulders on the washers, as Will be describedhereinafter.

Lock washer 20 has a number of sloping, circumferentially extending camfaces 40 formed on one side thereof, which at the junctions thereofdefine stop shoulders 42. On one side of washer 22 a number of sloping,circumferentially extending cam faces 44 are formed, which at thejunctions thereof define stop shoulders 46.

When the stop shoulders 42 and 46 are in contact they serve to arrestrotation between the washers 20 and 22 while nut 24 is being screwedonto stud bolt 12, as

mentioned hereinabove, and the contacting cam faces 40 and 44 serve toprevent rotation of nut 24 relative to the stud bolt 12 in acounterclockwise or unlocking direction after the nut has been screwedinto locked or operative engagement with the plate A through the otherelements of the lock washer assembly; namely, the stud bolt, thewashers, and the plate.

The detailed structure of lock washer 20 may best be seen in FIGURE 7,which is preferably hexagonal to provide pairs of opposed flats 48 whichmay be engaged by a wrench (not shown) for reasons to be explained indetail hereinafter.

Each of the body shoulders 42 is defined by a lower, radially extendingline and an upper radially extending line. For clarity of descriptionand illustration herein the upper radial lines are identified in FIGURES4 and 7 by the notations H-1 to H6 inclusive, and the lower radial linesL-l to L6 inclusive.

Inasmuch as the lock washer 20 is hexagonal, the spacing between theradial lines H-l to H-6 and lines L-1 to L-6 is 60. For simplicity ofillustration, the body shoulders 42 are shown in FIGURES 4 and 7 aslying in vertical planes, but actually, when the lock washer 20 isfabricated by a pressure impacting operation, the body shoulders are notformed at a vertical plane, but slope upwardly at an angle. If thewasher 20 as shown in FIGURE 7 is considered as resting on a flatsurface D, each of the radially extending lines I-I-I to I-I-6 inclusivewill lie in a plane above surface D and parallel thereto. Likewise, eachof the lower radial lines L-l to L6 inclusive will also be disposedabove surface D and parallel thereto.

The configuration of each cam surface 40, as may best be seen in FIGURES4 and 5, is a 60 circumferentially extending segment of the washer 20,with each segment having a straight outer boundary line 41 and a curvedinner boundary line 13. The configuration of one of the cam faces 40 isbest shown in FIGURE 7 wherein it will be seen that one of the outerboundary lines 41, more specifically designated by the notation 41a,extends from the outer extremity of line H-l to the outer extremity ofline L1. The balance of the boundary lines are identified as 41b, 410,41a and 41 in FIGURES 4 and 7. Also in the same cam segment, an innerboundary 43, further identified as 43a, extends from the inner extremityof line H-1 to the inner extremity of line L-l. The balance of the innerboundary lines are identified by the notations 43b to 43] as shown inFIGURES 4 and 7. The outer boundary line 41a is of substantially greaterlength than the inner boundary line 43a, but both of these linesoriginate at the line H-1 which is at a fixed uniform elevation abovethe surface D and terminate on the line L-l which is also at a fixeduniform elevation above surface D. Thus, the outer boundary line 41awill be at a lesser angle relative to surface D than the boundary line4311, as may be clearly seen in FIGURE 7. This is also true of eachboundary line 41b to 41 relative to its corresponding inner boundaryline 43b to 43 This description of the cam face 40 lying between theradially extending lines H1 and L-1 is equally applicable to the balanceof the cam surfaces 40 shown in FIGURES 4 and 7. The cam surfaces 44shown on the upper lock washer 22 in FIGURE 1 are matching duplicates ofthe cam surfaces 40. When lock washers 20 and 22 are rotated relative toone another, the cam surfaces 40 and 44 are finally disposed in theposition shown in FIGURE 2.

After nut 24 has been made up on bolt 12 (FIGURE 2), any attempt toremove it, either by application of a rotational force thereto in acounter clockwise direction or by imparting vibration thereto, will beresisted by the action of the two lock washers 20 and 22. When the nut24 is made up, it is brought into pressure contact with the radialserrations 30 of the upper lock washer 22, and

4- these serrations (FIGURE 3) are so formed as to permit rotation ofthe nut in a clockwise direction relative thereto, but resist rotationof the nut when it is rotated in a counter-clockwise direction relativethereto. When such counter-clockwise rotation is attempted, theserrations 32, as best illustrated in FIGURE 2, tend to bite into themetal of .the under surface 36 of nut 24. Thus, counterclockwiserotation of nut 24 is resisted by the nut due to the ability thereof torotate relative to the serrations 32.

After nut 24 is screwed on bolt 12, the cam faces 40 and 44 are inengagement and the faces 44 slide relative to the cam faces 40 until thebody shoulders 42 and 46 are in abutting contact. Should any attempt bemade to rotate the nut 24 and the washer 22 relative to the bolt 12, thecam faces 44 will slide upwardly on the cam faces 40, whereby theserrations 32 on washer 22 are forced into greater pressure contact withthe under surface 36 to hold the nut in a fixed position on the bolt.

The lower washer 20 cannot rotate relative to the surface 18 of plate A,for when the nut 24 is made up, the serrations 30 thereof are broughtinto pressure contact with the plate whereby due to their configuration,the serrations tend to dig into the plate. After positive engagement ofthe serrations 30 and plate A, the serrations tend to resist rotation ofWasher 20 in a counter-clockwise direction so long as downward force isexerted on the washer.

The plate A (FIGURE 2) rests on the base 14 and is not rotatablerelative thereto. For the cam faces 40 and 44- to maintain theserrations 30 and 32 in pressure contact with the surface 18 of plate Aand surface 36 of nut 24, it is necessary that the angle of these camfaces relative to the horizontal be such that as the upper lock washer22 and nut 24 concurrently rotate relative to the lower washer 20, theupper washer will move upwardly per degree of rotation at a faster ratethan the nut on bolt 12. Thus, the angular positioning of the cam faces40 and 44 must be at an angle B (FIGURE 5) that is greater than angle Cwhich threads 16 of a through bolt 12' make relative to the horizontal.If the angle B is less than the angle C, the nut 24 would uponconcurrent rotation with washer 22 move upwardly faster than the washer22, and would be disengaged from the serrations 32. After disengagementof nut 24 from serrations 32, it is free to be unscrewed from bolt 12.

To disengage the nut 24 from the stud bolt 12 or through bolt 12 byvibration after it has been made up thereon, there must be some relativemovement of the nut and the upper washer 22 relative to the lower washer20. Such relative movement of the nut 24 and washer 22 normally wouldonly be possible if there has been an elongation of the bolt 12 or 12'.When a nut 24 is made up on either a stud bolt 12 (FIGURES 1 and 2) or athrough bolt 12' (FIGURE 5) the bolt is subjected to tension.

Such tension, as well as any additional tension that may be placed onthe bolt due to loading, may, after a prolonged period of time cause themetal of the bolt to creep and permanently deform in the direction inwhich the tensional force is applied. The degree of creep in variousmetals and alloys is dependent upon the temperature at which the metalis stressed, the magnitude of the stress, and whether the stress isintermittently or constantly applied. If the stud bolt 12 or throughbolt 12 tends to elongate after the nut 24 has been made up thereon, asshown in FIGURES 2 and 5, relative movement between the upper washer 22and lower Washer 20 would be possible. However, if after suchelongation, and assuming the bolt, nut 24 and washers 20 and 22 aresubjected to vibration, rotation of the nut could only occur withconcurrent rotation of the washer 22. As the washer 22 would tend torotate in a counterclockwise direction as illustrated in FIGURE 2, thecam faces 44 would slide relative to cam faces 40, and the nut 24 andupper washer 22 would be moved upwardly on bolt 12 or 12' and held inlocked position thereon. If the vibration is of such nature that the nut24 and upper washer 22 remain stationary on the elongate bolt 12 or 12',the lower washer 20 due to the configuration of the serrations 30, canonly rotate in a clockwise direction. As such clockwise rotation of thelower washer 20 takes place, the cam faces 40 move relative to the camfaces 44. A downward force imparted to washer 20 due to the rotationalmovement relative to washer 22 that tends to cause the serrations 30 tobite into the surface 18 of plate A or the upper surface of plate 64 toassume a new position relative thereto, and in which new position thenut 24 is locked in fixed position relative to bolt 12 or 12'. Thus, itwill be seen that even when the bolt 12 or 1 2 elongates as a result ofloading and is subjected to vibration, due to such vibration the lockwashers 20 and 22 continue to cooperatively exert a locking elfect onnut 24.

Obviously, a number of modifications of the lock washer concept justdescribed are possible. As an example, one alternate form of lock washer54 may be employed, as shown in FIGURE '6, which is identical to washer22, other than that the serrations 32 are dispensed with, and instead aflat upper surface 56 is provided which is roughened to furnish a numberof small, upwardly extending protuberances 58 that may be forced intobiting engagement with the under surface 36 of nut 24. If the alternateform is used, another washer 60 (FIGURE 5) would be provided which wouldbe the same as washer 20 except that the serrations 30 thereon would beeliminated and a plane surface substituted therefor that has smallproturberances 58 projecting therefrom. Washer 60 would engage washer 54and function in the same manner as washer 20 previously described. Thetwo washers 54 and 60 have cam faces 44' and 40 of the sameconfiguration as the cams 44 and 40 as shown in FIGURE 1.

The alternate form of the washer is shown mounted on a through bolt 12'which has a head 62, and two plates 64 and 66 are held in abuttingcontact by this bolt which extends through bores 64a and 66a formedtherein. This alternate form of the invention operates in precisely thesame manner as the preferred form thereof shown in FIGURES 1 and 2 andaccordingly the use and operation of the alternate form need not bedescribed.

If the plate A or members 64 and 66 are steel or iron, the lock washers20 and 22 would preferably be formed of a ferrous metal, and at leastthe serrated portions 30 and 32 heat treated to a Brinell hardnessgreater than that of plate A, member 64, and nut 24. In addition, it hasbeen found that the washers 20 and 22 can be fabricated from anon-ferrous material such as aluminum, or an alloy thereof, or from apolymerized resin. When a non-ferrous material or polymerized resin isutilized in the fabrication of washers 20 and 22, the serrations 30 and32 do not dig in or become embedded in the material of nut 24, plate A,or member 64, but are in binding, frictional engagement therewith. Theserrations 30 (FIG- URE 7) define radially extending teeth 30m thatpermit clockwise rotation of the washer 20, but which bite into thesurfaces 18 or upper surface of member 64 when the washer is in pressurecontact therewith and a rotational force is applied to the washer is ina counter-clockwise direction. Serrations 32 have teeth 32a that aresimilar to teeth 30a, and tend to bite into the lower surface 36 of nut24 when in pressure contact therewith, and when the nut attempts torotate in a counter-clockwise direction relative to washer 22. From theconfiguration of teeth 3011, it will be seen that they will resistcounterclockwise direction of washer 20 relative to surface 18 or theupper surface of member 64, even if the washer is formed from a softmetal such as aluminum or a material such as a polymerized resin.

As previously mentioned, the washer 20 isformed with a number of pairsof flats 48. Also, washer 22 is preferably formed with a number of pairsof flats 50. The flats 48 and 50 present exterior surfaces lying in thesame vertical plane when the nut 24 is made up as shown in FIGURE 2, andthese flats are concurrently engageable by a wrench. Under someconditions, depending upon the toughness of the teeth 30a and 32a andthe type of surface with which they come into pressure contact, it ispossible to loosen a made-up nut 24 by concurrently rotating the washersin a counter-clockwise direction. However, if washers 20* and 22 areformed from a hard material such as steel, with the teeth 30a and 32abeing sharp, it is impossible to unscrew the nut 24 from bolts 12 or 12'if it has been tightly made-up thereon. To further prevent removal of anut 24 from a through bolt 12, the head 62 may be disposed in a recesss(not shown) formed in the lower surface of lower member 66-, or theinner face 62a of the head may be roughened or provided with serrations(not shown), or the like to positively or frictionally grip the lowersurface of member 66 when in pressure contact therewith.

The 'washers 20 and 22 previously described have substantially the sametransverse cross section as the nut 24 with which they will be used, andthe washers and the nut having the same number of externalwrench-engageable surfaces that are alignable with one another, and thuspermit a single wrench to be used to disengage the washers 20' and 22and nut 24 from the threaded member on which they are disposed.

The inclined mating surfaces of each washer extend entirely over oneside thereof, and extend radially from the outermost edges of the washerto a centrally disposed opening therein, as shown in FIGURES l and 7.Each inclined mating surface has an inner edge which forms an anglerelative to a plane at right angles to the central axis of said washergreater than the angle of the threads on the threaded member relative tothe longitudinal axis thereof. The outer edges of each of thewrench-engageable surfaces may be less than the angle of the inneredges, if so desired.

The operational advantages of the washers 20 and 22 disclosed andclaimed herein may be summarized as follows:

(1) Washers 20 and 22 can be of minimum thickness, for only the edges ofthe inclined surfaces thereon adjacent the opening therein need be of anangle greater than that of the threads on the threaded member 12.

(2) External surfaces of the washers are automatically aligned inco-planar relationship with the external surfaces of the nut 24 withwhich the washers 20- and 22 are used, and when the washers are placedon a threaded member 12 with the inclined surfaces thereof in abuttingcontact.

(3) All portions of the washers 20 and 22 are subjected to substantiallythe same force when the nut 24 with which they are used is tightened ona threaded member 12.

(4) Washers 20 and 22 and nut 24 can be unscrewed as a unit from athreaded member 12 on which they are mounted by use of a single wrench.

Although the present invention is fully capable of achieving the objectsand providing the advantages herein'before mentioned, it is to beunderstood that it is merely illustrative of the presently preferredembodiments thereof and I do not mean to be limited to the details ofconstruction herein shown and. described, other than as defined in theappended claim.

I claim:

In combination with a nut having a plurality of wrench-engageable,angularly disposed external surfaces and a threaded member engageable bysaid nut, a pair of identical lock washers of the same transverse crosssection as that of said nut which cooperate with each other to hold saidnut in a non-rotatable position on said threaded member when saidthreaded member extends through a bore formed in an element such as asheet, each of which look washers has one end face with the same numberof circumferentially spaced, radially extending rectangular bodyshoulders of uniform height as the number of said angularly disposedsurfaces on said nut, which shoulders lie in planes that contain thecentral axis of said washers and extend through the corners of saidwashers defined by said angularly disposed surfaces, with a like numberof inclined surfaces on each of said end faces, each which inclinedsurfaces extends circumferentially from the top of one of said bodyshoulders to the bottom of that one of said body shoulders next adjacentthereto and radially from the outermost portion of said Washer to saidopening therein, with the edge of each of said inclined surfacesadjacent said opening forming an angle relative to a plane at rightangles to the central axis of said washer that is greater than the angleof the threads on said threaded member relative to the longitudinal axisthereof, said Washers being mounted on said threaded member with theinclined surfaces on one washer being in abutting contact with theinclined surfaces on the other washer, and the end faces of said Washersopposite those on which said inclined surfaces are defined having aplurality of circumferentially spaced serrations formed therein whichextend radially from said opening to the outer edges of said washers,which serrations are of a hardness greater than that of the materialdefining said element and said nut so that said serrations are at leastpartially embedded in said nut 8 and element when said nut is tightenedon said Washers, which washers have the same number of external,angularly disposed surfaces as said nut with said external surfaces ofsaid washers and said surfaces of said nut being in co-planar alignmentto permit said nut and Washers to be concurrently fripped as a unit whensaid nut is being unscrewed from said member, with the outer edge ofsaid inclined surfaces on said Washer being at an angle relative to theside thereof on which said serrations are formed that is less than theangle of the threads on said threaded member.

References Cited UNITED STATES PATENTS 1,107,792 8/1914 Houston 151352,271,732 2/ 1942 Chappuis 15135 FOREIGN PATENTS 684,466 11/1939Germany.

6,425 5/ 1888 Great Britain. 5 14,923 11/ 1939 Great Britain.

CARL W. TOMLIN, Primary Examiner.

R. S. BRITTS, Assistant Examiner.

UNITED STATES PATENT OFFICE Patent No.

July 4, 1967 Carl 0 Oldenkott It is hereby certified that error appearsin the above numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

Column application application Lock Washer Signed (SEAL) Attcst:

Edward M. Fletcher, Jr.

Attesting Officer 1, line 12, after "abandoned" insert which is in turna continuation-in-part of my Serial No. 261,954, filed Mar. 1, 1963,entitled and Lock Washer Assembly, now abandoned and sealed this 11thday of February 1969.

EDWARD J. BRENNER Commissioner of Patents

